Car jumps when Shifting from R - D???

[lx24]

My 2000 Trans Am has had this problem for a while now, the problem is when i shift from D-R, or from R-D, the car jumps, and makes a thumping sound, it also does it while braking, and when i go over speed bumps and such, i initially thought is was caused by a warped rotor so i replaced all four with drilled and slotted, then i figured it was the shocks going out so i replaced all four, with bilsteins, and new eibach springs, but my car still does the same thing, i need help because its getting more and more frustrating!!!! Thanks!!

[2000T/A Guru]

Check your tranny mounts and supports

[sfletch2000]

could it be you u-joint going out?

[Mr. Luos]

Check your tranny mounts and supports
I would say that tranny mount is the culprit here.
Not expensive either. Give it a shot.

[lx24]

i replaced my tranny mount before everthing with a polyurethane one, could it still be that???

[Mr. Luos]

Does it clunk???

Something feel loose?
Might be the mount again....but could be something else.
Do the RPM's jump with it at all?

[lx24]

No, RPM'S stay the same, it feels like either something with the drivetrain or suspension???

[LETHALxLS1]

Sounds like the transmission mount is weak/ripped. IMHO

[mrr23]

seeing as you put a poly one in, look at the torque arm mount.

[juiced99ws6]

seeing as you put a poly one in, look at the torque arm mount.

+1, either that or just something coming loose on your torque arm could do it. The torque arm also sounds horrible when its just a little loose and you may not even be able to tell its not tightened all the way with weight on wheels. I am missing two torque arm bolts right now and that alone is enough to make horrible noises under braking.

[LETHALxLS1]

^ I agree. The nuts came loose on my ta where it bolts to the rear end and it would make terrible noise/banging when I let off the throttle or braked .

[lx24]

HMMM!!! thanks ill check that out before i try to replace my u-joints!

[juiced99ws6]

cool man, hope it helps. make sure you come back and let us know how it goes. I am always trying to learn from other peoples problems!

[juiced99ws6]

Ok now I have even more to add to this. I was told by the shop that dynoed my car that I was missing 2 torque arm bolts and I thought maybe I forgot to put them back in after my transmission swap. I checked under there and everything looked fine to me, everything I took out was back in and very tight. I played around with my car a little last night and then went to run some errands in it today and to my dismay I found out what the noise was in my car. I have a Spohn Adj. Chrome Moly torque arm and when I went to leave the parking lot at the plasma center there was an AWFUL grinding on the pavement so I stopped to check it out and sure as shit there was my damn torque arm in all its glory laying on the ground. It snapped right off where the rear mounting bolts were at. 500$ well spent. Anyways moral of the story is it was making the same noises that you described.

[lx24]

Thanks i better fix the problem before that happens to me! thanks very much!!

[clg82]

i just had my tranny rebuilt and it seems to do the same thing when i go over speedbumps! I get a huge thumping noise! Anyone have any pix of where the tranny mount is located? Thanks, Chris

[LETHALxLS1]

It is a piece of metal that runs from the rear end to the rear of the transmission. Where it connects to the tail of the transmission it has a rubber grommet/mount and it connects to the rear with 2 long bolts. You cant miss it.
http://i200.photobucket.com/albums/aa149/LETHALxLS1/rear20013.jpg

[juiced99ws6]

That picture is actually showing the bolts that I was referring to on the torque arm where it mounts to the rear axle housing. The transmission mount is towards the center of the car. If you are under your car you will see a black metal bar going from left to right that has 4 bolts in it. That is your cross member. You would remove those 4 bolts and make sure you have a jack under the transmission supporting the tail shaft otherwise it will be hard to get the bolts out since the crossmember would drop with them. You dont want to use jack stands because you will eventually need to lower the transmission. After those bolts are out you would then lower the tail of the transmission. The Transmission mount will then be visible to you rather easily. It is the point that connects the crossmember to the tailshaft of the transmission. I believe it is two studs with nuts that supports it to the crossmember. You can go to any Auto parts store and buy a new one for about 20 bucks and it will also come with new hardware.

My recommendation if you are having thumps that sound like a transmission mount would be to put the car up as high as you can on either a lift or 4 jackstands and do a thorough inspection of all bolts on your torque arm, the torque arm bushing, and the cross member. If all looks fine then drop down the tranny as mentioned above and inspect and replace your mount. Hope this helps you guys. I know I didnt provide pictures but after reading this is should be relatively self explanatory once you poke around under the car.

[juiced99ws6]

Thanks i better fix the problem before that happens to me! thanks very much!!

:yup: not very fun

http://i125.photobucket.com/albums/p42/juiced99ws6/P1000412.jpg
http://i125.photobucket.com/albums/p42/juiced99ws6/P1000411.jpg
http://i125.photobucket.com/albums/p42/juiced99ws6/P1000410.jpg
http://i125.photobucket.com/albums/p42/juiced99ws6/P1000409.jpg

[Heartbreak1]

:yup: not very fun

http://i125.photobucket.com/albums/p42/juiced99ws6/P1000412.jpg
http://i125.photobucket.com/albums/p42/juiced99ws6/P1000411.jpg
http://i125.photobucket.com/albums/p42/juiced99ws6/P1000410.jpg
http://i125.photobucket.com/albums/p42/juiced99ws6/P1000409.jpg
:eek2:

[LETHALxLS1]

^ Yea I would have been soooooooooooooooooo pissed!

[juiced99ws6]

:yup: I was but I was lucky enough to have an adjustable one so I can just replace the bracket instead of the whole thing. Very good thing for me. 500$ or 40$, I would take the latter any day...

[lx24]

:nana:
Finally!!!! it is my damn torque arm bushings thats bad, I am so relieved to finally know what the problem was!! THANK YOU everyone for your help, it was very usefull in determining what the problem was!!

[juiced99ws6]

cool! good find, I am glad its done for you man

I would have NEVER thought about the bushing, mine is crossmember mounted so that is something I dont have to deal with

[lx24]

yup, mine is still mounted to the tranny, i have a poly one now!!